Angiographic methods, which generate images of blood vessels, are of great importance in the assessment of vascular diseases, such as atherosclerosis. They can provide information on vessel morphology and function which aids clinicians with diagnosis, prognosis, and treatment planning in these patients. Vessel-selective angiography provides additional information about the relative importance of each feeding artery which can be useful in a number of areas, such as the assessment of collateral blood flow or the evaluation of blood supply to a tumor or arteriovenous malformation. However, many angiographic methods provide only qualitative information on blood flow, making objective comparisons between vessels and across subjects difficult. In addition, many of these methods have a number of other drawbacks such as the requirement for an invasive procedure, the use of ionizing radiation, or the administration of a contrast agent.